The use of alcohol as an antimicrobial dates to biblical times and earlier. Alcohol-containing antimicrobial compositions have been widely used in hospitals since at least the 1990's. In 1993, Bruch et al (U.S. Pat. No. 5,403,864) stated:—
“Infection control and epidemiology experts have repeatedly emphasized that the single most important element in reducing the spread of infection is hand washing because a common method of transfer among individuals in the health care environment is with the hands. This fact has been painfully demonstrated in the analysis of epidemic spread.However obvious and simple this may seem, medical care personnel, including physicians and nurses, are reluctant to wash or scrub their hands as frequently as required by their own protocols. It is estimated that the average time of washing between patients is 10 sec or less. The effectiveness of soap-and-water washing is measured in terms of minutes. Most simply do not wash frequently enough . . . .When a health care worker handles equipment or patients, bacteria which are not a part of the normal skin flora are picked up and adhere loosely to the topmost skin layer, the stratum corneum.”
These statements remain as true in 2012 as when written in 1993. However in the intervening 20 years, new and improved antimicrobial preparations have been developed and the significance of two additional facts has become apparent. Firstly, some microorganisms may reside more deeply in sub corneum strata. Secondly, the major reason for non-compliance with protocols is drying and chapping of the hands and skin irritation caused by repeated use of alcoholic rubs or water based antiseptic washes. Attempts to minimize irritation by inclusion of emollients have not been effective at increasing compliance either (i) because the emollients contributed to a feeling of greasiness after use or (ii) because they reduced the speed with which the hand wash was effective, or (iii) at the concentrations required, the emollients were ineffective at skin irritation reduction or for a combination of these three reasons.
In 1995 Bruch et al disclosed an antimicrobial composition comprising Triclosan, chloroxyphenol and an alcohol but this composition was not effective against subcutaneous organisms and although the inventors claimed that no signs of irritation were exhibited after multiple uses in the laboratory, many cases of skin irritation were exhibited in hospital use.
In 1998 Jampani et al (U.S. Pat. No. 6,022,551) noted a need for an antimicrobial composition that is effective while also being non-irritating to users, and described a composition containing specific thickeners, and phospholipids
The present Inventors have found that subjective feel of the composition also plays an important role in compliance, irrespective of other factors, and it is not sufficient for a composition to be “non-irritating”. Thus, staff who may have to apply compositions to their hands as frequently as 100 times a day if they are to fully comply with protocols have been found to have a much higher compliance rate if using preparations which they judge to feel good, than if using preparations which they do not judge to feel good, or which they judge to feel inferior to other preparations they have used which they judge to feel better. One of the factors influencing feel is the tendency to pill exhibited by some alcoholic gel preparations, but other factors include greasiness, and other subjective factors which play a major role in affecting how the composition feels when used and hence compliance rates. Preparations which are generally judged by staff in use to feel superior to prior art preparations are herein referred to as having “improved feel.” One Internationally accepted benchmark for biocidal efficacy is that a specified dose of an antiseptic composition left in contact with the hands for a specified time is required to produce at least the same biocidal efficacy as 6 ml of 60% v/v isopropyl alcohol with 60 secs contact time. (The test method is fully described in European Standard EN 1500:1997, entitled ‘Chemical disinfectants and antiseptics Hygienic Handrub—Test method and requirements (phase 2/step 2)’ against E. coli NCTC 10538. hereinafter referred to as “EN1500:1997.”)
Compositions for use as antiseptic hand rubs have contained materials added to “improve skin conditioning” and moisturization e.g. humectants such as glycerine, anti-inflammatories such as isolene, and anchoring agents/conditioners such as phenyldimethicone quaternary compounds. However skin “conditioners” are intended to affect the moisturization, emolliency and condition of the skin, in order to reduce irritation, rather than to affect the feel of the composition on the skin.
Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.